 | near North Bend, King County, Washington, USA |
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GEOLOGY
Intrusive Breccia - About 25 million years ago, near where Mount Teneriffe is today, magma associated with the Snoqualmie batholith intruded into older Tertiary marine sedimentary rock, fracturing and breaking up (brecciating) the rock as the magma intruded and the associated gasses escaped. Subsequent quartz mineralization from hydrothermal fluids filled the voids. The country rock north of Mount Teneriffe is specifically a marine argillite (formed from clay-rich marine sediment) that has been both brecciated and baked (thermally metamorhposed) by the intrusion.
The Mount Teneriffe deposit is part of the State of Washington's Mount Si Natural Resource Conservation Area.
MINERALS
| SiO2 - Occurs as generally small crystals. Japan-law twin crystals are common. Reichenstein-Grieserntal twin crystals can also be found. |
* photographed
Japan-Law Twin QUARTZ |
Japan-Law Twin QUARTZ |
Japan-Law Twin QUARTZ |
Reichenstein-Grieserntal Twin QUARTZ |
Japan-Law Twin QUARTZ |